Organic solar cells are being developed for clean renewable energy due to their potential for making cost-effective, large area devices. The performance of solar cells depend on the light-absorbing semiconducting materials. Alternating conjugated polymers based on a backbone structure of benzo[1,2-b:3,4-b′]dithiophene-thienothiophene have demonstrated promising performance in organic solar cell applications. Benzo[1,2-b:3,4-b]dithiophene is one of the key monomers. The symmetric, planer structure of BDT provides excellent charge carrier mobility and optical absorption properties to the polymer.
The BDT conjugated polymer based solar cell is relatively inefficient due to inadequate optical absorption, relatively low charge carrier mobility and non-optimized device morphology. Thus, a BDT-TT based conjugated polymer is needed with an expanded conjugation system to cover a broader solar spectrum and with a tuned polymer packing to optimize the device morphology and enhance charge carrier mobility.